CN101860208A - Dc-dc converter and switching control circuit - Google Patents
Dc-dc converter and switching control circuit Download PDFInfo
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- CN101860208A CN101860208A CN201010104741A CN201010104741A CN101860208A CN 101860208 A CN101860208 A CN 101860208A CN 201010104741 A CN201010104741 A CN 201010104741A CN 201010104741 A CN201010104741 A CN 201010104741A CN 101860208 A CN101860208 A CN 101860208A
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
- H02M3/00—Conversion of dc power input into dc power output
- H02M3/02—Conversion of dc power input into dc power output without intermediate conversion into ac
- H02M3/04—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters
- H02M3/10—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode
- H02M3/145—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal
- H02M3/155—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only
- H02M3/156—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only with automatic control of output voltage or current, e.g. switching regulators
- H02M3/158—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only with automatic control of output voltage or current, e.g. switching regulators including plural semiconductor devices as final control devices for a single load
- H02M3/1588—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only with automatic control of output voltage or current, e.g. switching regulators including plural semiconductor devices as final control devices for a single load comprising at least one synchronous rectifier element
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- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03K—PULSE TECHNIQUE
- H03K17/00—Electronic switching or gating, i.e. not by contact-making and –breaking
- H03K17/22—Modifications for ensuring a predetermined initial state when the supply voltage has been applied
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
- H02H7/00—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions
- H02H7/10—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions for converters; for rectifiers
- H02H7/12—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions for converters; for rectifiers for static converters or rectifiers
- H02H7/1213—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions for converters; for rectifiers for static converters or rectifiers for DC-DC converters
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
- H02M1/00—Details of apparatus for conversion
- H02M1/36—Means for starting or stopping converters
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
- H02M1/00—Details of apparatus for conversion
- H02M1/44—Circuits or arrangements for compensating for electromagnetic interference in converters or inverters
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
- H02M3/00—Conversion of dc power input into dc power output
- H02M3/02—Conversion of dc power input into dc power output without intermediate conversion into ac
- H02M3/04—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters
- H02M3/10—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode
- H02M3/145—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal
- H02M3/155—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only
- H02M3/156—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only with automatic control of output voltage or current, e.g. switching regulators
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
- H02M7/00—Conversion of ac power input into dc power output; Conversion of dc power input into ac power output
- H02M7/02—Conversion of ac power input into dc power output without possibility of reversal
- H02M7/04—Conversion of ac power input into dc power output without possibility of reversal by static converters
- H02M7/06—Conversion of ac power input into dc power output without possibility of reversal by static converters using discharge tubes without control electrode or semiconductor devices without control electrode
- H02M7/064—Conversion of ac power input into dc power output without possibility of reversal by static converters using discharge tubes without control electrode or semiconductor devices without control electrode with several outputs
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- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03K—PULSE TECHNIQUE
- H03K17/00—Electronic switching or gating, i.e. not by contact-making and –breaking
- H03K17/08—Modifications for protecting switching circuit against overcurrent or overvoltage
- H03K17/082—Modifications for protecting switching circuit against overcurrent or overvoltage by feedback from the output to the control circuit
- H03K17/0822—Modifications for protecting switching circuit against overcurrent or overvoltage by feedback from the output to the control circuit in field-effect transistor switches
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
- F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
- F15B2211/00—Circuits for servomotor systems
- F15B2211/30—Directional control
- F15B2211/32—Directional control characterised by the type of actuation
- F15B2211/327—Directional control characterised by the type of actuation electrically or electronically
- F15B2211/328—Directional control characterised by the type of actuation electrically or electronically with signal modulation, e.g. pulse width modulation [PWM]
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
- H02M1/00—Details of apparatus for conversion
- H02M1/0003—Details of control, feedback or regulation circuits
- H02M1/0029—Circuits or arrangements for limiting the slope of switching signals, e.g. slew rate
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02B—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS
- Y02B70/00—Technologies for an efficient end-user side electric power management and consumption
- Y02B70/10—Technologies improving the efficiency by using switched-mode power supplies [SMPS], i.e. efficient power electronics conversion e.g. power factor correction or reduction of losses in power supplies or efficient standby modes
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- Engineering & Computer Science (AREA)
- Power Engineering (AREA)
- Physics & Mathematics (AREA)
- Electromagnetism (AREA)
- Dc-Dc Converters (AREA)
Abstract
The invention provides the technique of reducing peak noise in a DC-DC converter in the manner of a switching regulator. In the DC-DC converter which is provided with the switching regulator having a driving switching element (M1) for driving the current to pass through an inducer, a rectification element (M2) and a filter capacitor connected to an output terminal, at least a driving signal of a drive circuit (DRV1) is generated for conducting or stopping the driving switching element (M1), wherein a transition time (tf1) of the drive signal in which the driving switching element (M1) shifts from an off state to an on state becomes longer than a transition time (tr1) of the drive signal in which the driving switching element (M1) shifts from the on state to the off state.
Description
Technical field
The present invention relates to the DC-DC transducer and the ON-OFF control circuit thereof of the switching regulator mode of conversion direct voltage, relate in particular to the spike noise of switch motion of the DC-DC transducer that is used for reducing following synchronous commutation type and otherwise effective technique.
Background technology
Export the circuit of the direct voltage of different potentials as the conversion input direct voltage, the DC-DC transducer of switching regulator mode is arranged.In described DC-DC transducer, as shown in Figure 3, have the DC-DC transducer of following synchronous commutation type, it has: the DC power supply voltage Vin from direct-current power supplies such as batteries is applied to inductor (coil) L1 flows through electric current, make the driving switch element M1 of coil savings energy; At the energy deenergized period that this driving is cut off with switch element, the rectification switch element M2 that the electric current of coil is carried out rectification.The DC-DC transducer of this synchronous commutation type, by make drive with switch element and rectification with switch element conducting complementally, end, compare with the DC-DC transducer of diode rectification type and improved power efficiency.
At present, in the DC-DC of switching regulator mode transducer, the conducting of known generation and switch element, by action spike noise together.This spike noise becomes the reason that common-mode noise produces, and peripheral circuits is produced harmful effect.In addition, require to constitute generate switch element conducting, have by the elements such as transistor of the control circuit of control signal necessary above withstand voltage.Therefore, some technology (for example patent documentation 1) that reduce spike noise have been proposed.
[patent documentation 1] spy opens the 2004-112958 communique
Summary of the invention
The inventor has studied the reason that spike noise produces in the DC-DC transducer of switching regulator mode shown in Figure 3 in great detail.With N channel transistor M2, gate driving pulse GP1, GP2 by homophase are by conducting complementally, by driving in the p channel transistor M1 of the driving usefulness that connects between the terminal of sub-VIN of voltage input end and coil L and the rectification that connects between the described terminal of coil L and earth point.And, become conducting state simultaneously and flow through perforation electric current in order to prevent M1 and M2, as shown in Figure 4, in order to have Dead Time Δ t, with pulse GP1, GP2 form for: fall time, tf1, tf2 and rise time tr1, tr2 were not overlapping.
By above-mentioned pulse GP1, GP2 to transistor M1 and M2 carry out conducting, when driving, thought: for the loss that the conducting resistance that reduces transistor M1, M2 causes is raised the efficiency in the past, it is desirable to make M1, M2 conducting at short notice, end, as amplifying expression among Fig. 5, make gate driving pulse GP1, GP2 rising, descending becomes precipitous, and makes tf1 fall time, tf2 and rise time tr1, tr2 not overlapping.But when making pulse precipitous as described above, be easy to generate spike noise.And known following problem arranged: because this spike noise is a high frequency, therefore can't remove by the filter circuit that coil L and filtering capacitor C constitute, and invade input voltage vin as noise, other circuit that become common source voltage produce dysgenic reason.
In addition, the technology of record in described patent documentation 1, the spike noise testing circuit is set, and with switch element (driver transistor) the bigger extra transistor of conducting resistance is set in parallel with the driving that makes electric current flow through coil, when detecting spike noise by making the extra transistor conducting reduce noise, this technology exists circuit scale to become big, the inconvenience that causes die size to increase.
Be conceived to the problems referred to above and proposed the present invention, its purpose is to provide the technology that can in the DC-DC of switching regulator mode transducer spike noise be reduced.
In addition, the objective of the invention is to, provide to make DC-DC transducer that the spike noise of following switch reduces and the ON-OFF control circuit that constitutes this DC-DC transducer.
In order to reach above-mentioned purpose, the invention provides a kind of ON-OFF control circuit, it possesses first drive circuit, described first drive circuit, generation is carried out conducting to the driving that makes electric current and flow through the inductor that voltage transformation uses with switch element, by the drive signal that drives, it is characterized in that, possess generation described driving is carried out conducting with switch element, first drive circuit by the drive signal that drives, described first drive circuit is constituted: compare from the transit time of the drive signal of conducting state when cut-off state shifts with switch element with making described driving, make described driving longer from the transit time of the drive signal of cut-off state when the conducting state transitions with switch element.
According to above-mentioned means, can suppress to drive the peak value of the electric current that transient flow is crossed when being switched on switch element, therefore in the DC-DC of switching regulator mode transducer, can reduce to follow the spike noise that drives with switch.
In addition, described ON-OFF control circuit also possesses second drive circuit, its be created on described driving with switch element be cut off during the electric current of coil is carried out the drive signal of the rectification of rectification with switch element, described second drive circuit is constituted: compare from the transit time of the drive signal of conducting state when cut-off state shifts with switch element with making described rectification, make described rectification longer from the transit time of the drive signal of cut-off state when the conducting state transitions with switch element.Thus, in the DC-DC of synchronous commutation type transducer, therefore the peak value of the electric current that transient flow is crossed in the time of also can suppressing rectification and be switched on switch element can further reduce to follow the spike noise of switch.
At this, it is desirable to: described driving is made of the P channel type field effect transistors with switch element, described rectification is made of the N channel type field effect transistors with switch element, described first drive circuit is constituted: with comparing to the transit time of high level of the drive signal of exporting from this drive circuit from low level, longer from high level to low level transit time, described second drive circuit is constituted:, longer to the transit time of high level from low level with comparing to low level transit time of the drive signal of exporting from this drive circuit from high level.Thus, constitute by the P channel type field effect transistors with switch element in driving, in the DC-DC transducer of the switching regulator mode that described rectification is made of the N channel type field effect transistors with switch element, the peak value of the electric current that transient flow is crossed in the time of can suppressing switch element and be switched on.
Even more ideal is, described first and second drive circuit constitutes by the CMOS inverter, CMOS inverter as first drive circuit forms: the current driving capability of the current drives force rate N channel type field effect transistors of P channel type field effect transistors is big, and form as the CMOS inverter of second drive circuit: the current driving capability of the current drives force rate P channel type field effect transistors of N channel type field effect transistors is big.
Thus, can not use the drive circuit of labyrinth, and the peak value of the electric current that transient flow is crossed can easily suppress switch element and be switched on by simple design alteration the time.
Better is, constitute: from the drive signal of described first drive circuit output from high level to low level transit time and from the drive signal of described second drive circuit output from the transit time of low level to high level, be below 5% of cycle of described drive signal.
Thus, in the DC-DC transducer of having used the PWM control mode, the peak value of the electric current that transient flow was crossed when the control reference voltage ground inhibition switch element that can not too reduce PWM control was switched on.
Abide by the present invention, have the effect that can in the DC-DC of switching regulator mode transducer, reduce spike noise.
Description of drawings
Fig. 1 is the circuit structure diagram that an execution mode of synchronous commutation type DC-DC transducer of the present invention has been used in expression.
Fig. 2 is the oscillogram of the situation of the expression variation of the driving in the DC-DC transducer of execution mode being carried out conducting, the gate drive signal GP1 that ends driving and GP2 with switching transistor M1 and rectification with switching transistor M2.
Fig. 3 is the structured flowchart of the summary structure of the general synchronous commutation type DC-DC transducer of expression.
Fig. 4 is the sequential chart in the moment of the expression variation of the driving in the existing DC-DC transducer being carried out conducting, the gate drive signal GP1 that ends driving and GP2 with switching transistor M1 and rectification with switching transistor M2.
Fig. 5 amplifies gate drive signal GP1 in the existing DC-DC transducer of expression and the oscillogram of GP2.
Symbol description
20 ON-OFF control circuit; 21 error amplifiers; The 22PWM comparator; 23 output control logic circuit; The FB feedback terminal; R1, R2 divider resistance; L1 coil (inductor); The C1 filtering capacitor; DRV1, DRV2 output driver; M1 drives with switching transistor (drive and use switch element);
M2 synchronous rectification switching transistor (rectification switch element)
Embodiment
Below, with reference to the accompanying drawings preferred implementation of the present invention is described.
Fig. 1 has represented to use an execution mode of the DC-DC transducer of switching regulator mode of the present invention.
The DC-DC transducer of this execution mode possesses: as the coil L1 of inductor; Be connected between the terminal of sub-IN of the voltage input end that is applied in DC input voitage Vin and above-mentioned coil L1, flow into the driving switching transistor M1 by P channel mosfet (insulated-gate type field effect transistor) formation of drive current to coil L1; Be connected rectification switching transistor M2 between the described terminal of coil L1 and the earth point, that constitute by N-channel MOS FET.
In addition, the DC-DC transducer possesses: above-mentioned switching transistor M1, M2 are carried out conducting, end switch driven control circuit 20; And be connected the another terminal (lead-out terminal OUT) of above-mentioned coil L1 and the filtering capacitor C1 between the earth point.
Though do not limit especially, but in the present embodiment, in the element that constitutes the DC-DC transducer, ON-OFF control circuit 20 is formed on the semiconductor chip, constitute semiconductor integrated circuit (power supply control IC), coil L1, capacitor C1 and be connected with the outside terminal that on this IC, is provided with as outer member as transistor M1, the M2 of switch element.
In the DC-DC of this execution mode transducer, generate driving pulse GP1, the GP2 that makes transistor M1 and M2 conducting complementally, ends by ON-OFF control circuit 20, under stable state, in the time will driving with transistor M1 conducting, on coil L1, apply DC input voitage Vin, OUT flows through electric current to lead-out terminal, and filtering capacitor C1 is charged.
In addition, when will drive with transistor M1 by the time, alternately with rectification with transistor M2 conducting, in coil L1, flow through electric current with transistor M2 by the rectification of this conducting.And, for example by making switch periods import the driving pulse GP1 of the control terminal of M1, M2 (gate terminal), the pulse duration of GP2 definitely according to output voltage control, produce DC input voitage Vin step-down and VD Vout.
ON-OFF control circuit 20 has: be connected in series between the terminal FB and earth point of feedback from the voltage of lead-out terminal OUT, recently output voltage V out carried out resistance R 1, the R2 of dividing potential drop by voltage; Relatively pass through voltage VFB and the reference voltage Vref 1 that this electric resistance partial pressure gets, export the error amplifier 21 of the voltage corresponding with potential difference; The output of this error amplifier 21 is input to the PWM comparator 22 of an input terminal.
And ON-OFF control circuit 20 has: output control logic circuit 23, and it is according to the output pulse of said PWM comparator 22, and generation is used to make the not conducting overlappingly of mutual conduction period of switching transistor M1, M2, the control impuls C1 that ends and C2; And receive control impuls C1 and C2, gate drive signal GP1, the GP2 that generates switching transistor M1, M2 go forward side by side output driver DRV1, DRV2 line output, that constitute by the CMOS inverter.
Input is from the waveform signal of waveform generating circuit 24 on another input terminal of said PWM comparator 22, this waveform generating circuit 24 is built-in oscillator also generates the triangular wave or the such waveform signal of sawtooth waveforms of preset frequency, work as the pulse duration that output voltage reduces to export driving pulse when high according to feedback voltage V FB, and when feedback voltage V FB is low, enlarge the control of pulse duration.
In the DC-DC of this execution mode transducer, as shown in Figure 2, output driver DRV1, DRV2 generate rise time with hope and gate drive signal GP1, the GP2 of fall time (transit time) respectively.Particularly, when the fall time of establishing gate drive signal GP1 is tf1, rise time to be that fall time of tr1, gate drive signal GP2 is that tf2, rise time are when being tr2, gate drive signal GP1 is designed to tf1＞tr1, is that fall time is longer than the rise time, gate drive signal GP2 is designed to tf2＜tr2, is that the rise time is longer than fall time.At this, in the relation of tf1 and tr1, preferred tf1 is 1.5～2 times of tr1, and in the relation of tr2 and tf2, preferred tr2 is 1.5～2 times of tf2.
The relation of tr1 and tr2, tf1 and tf2 can be tr1 ≒ tr2, tf1 ≒ tf2.In addition, when tf1 and tr2 were excessive, the power loss that the conducting resistance composition causes increased, so tf1 and tr2 it is desirable to when being converted into 1MHz, suitably set in the switch periods scope below 5% in (cycle of driving pulse), better is suitably to set in the scope below 2%.
By by above-mentioned such fall time, rise time of setting as the transit time of gate drive signal GP1, GP2, in the DC-DC of present embodiment transducer, have the peak value that can reduce, can reduce the advantage of spike noise thus switching transistor M1, the M2 electric current that transient flow is crossed during conducting respectively.In addition, by tf1 and tr2 are set in below 5% of switch periods, the peak value of the control reference voltage ground inhibition that can not too the reduce PWM control electric current that transient flow is crossed during with M1, M2 conducting.
Then, the concrete grammar that is used for adding difference in the fall time of above-mentioned output driver DRV1, gate drive signal GP1, GP2 that DRV2 generates and rise time is described.
In the present embodiment, output driver DRV1, DRV2 are made of be connected in series between power supply voltage terminal VDD and earth point GND P channel mosfet and the formed CMOS inverter of N channel transistor.Generally, when P channel mosfet that relatively forms by current CMOS manufacturing process and N channel transistor, known under the situation of identical size, the current driving capability of N channel transistor is about 3 times big of P channel mosfet.
Therefore, in constituting the common CMOS inverter of logical circuit etc.,, the size of P channel mosfet is set at about 3 times of size of N channel transistor for the current driver power of the current driving capability that makes the P channel mosfet and N channel transistor is identical.Gate drive signal GP1 shown in Figure 5, the waveform of GP2 can be thought of as: will constitute the P channel mosfet of output driver DRV1, DRV2 and the size ratio of N channel transistor and be designed to 3: 1 o'clock waveform.
Relative with it, in the present embodiment, the P channel mosfet that constitutes output driver DRV1 and the size ratio of N channel transistor are set at for example 5: 1 bigger than 3: 1.Thus, the current driving capability of N-channel MOS FET becomes littler than the current driving capability of p channel transistor.
In the DC-DC of Fig. 1 transducer, constitute by the P channel mosfet with switching transistor M1 owing to drive, so M1 is switched between the low period of the gate drive signal GP1 that exports from output driver DRV1, therefore when the current driving capability of the N-channel MOS FET that constitutes DRV1 hour, then action in this wise: that is, be switched on back GP1 with the N channel transistor and compare to the time tr1 that low level changes from high level, it is elongated to the time tf1 that high level changes from low level that the p channel transistor of formation DRV1 is switched on back GP1.Thus, reduced to drive the peak value of the electric current that transient flow is crossed when switching to conducting with switch driver M1 from ending.
On the other hand, the P channel mosfet that constitutes output driver DRV2 and the size ratio of N channel transistor are set at for example 3: 4 littler than existing 3: 1.Thus, the current driving capability of P channel mosfet becomes littler than the current driving capability of N channel transistor among the output driver DRV2.
In the DC-DC transducer of Fig. 1, rectification is made of N-channel MOS FET with switching transistor M2, therefore, M2 is switched between the high period of the gate drive signal GP2 that exports from output driver DRV2, therefore when the current driving capability of the P channel mosfet that constitutes DRV2 hour, then action in this wise: that is, be switched on back GP2 with the N channel transistor of DRV2 and compare to the time tf2 that low level changes from high level, it is longer to the time tr2 that high level changes from low level that the p channel transistor of DRV2 is switched on back GP2.Thus, reduced the peak value of the electric current that rectification crosses from transient flow when switching to conducting with switching transistor M2.
And, when relatively driving is used switching transistor M2 with switching transistor M1 and rectification, drive with switching transistor M1 under the situation that is P channel mosfet and identical size, the current drives force rate is little with switching transistor M2 by the rectification that N-channel MOS FET constitutes, and therefore M1 is set at the size bigger than M2 (about 3 times).Therefore, consider to drive the transistorized size that recently designs transistor and the formation output driver DRV2 of formation output driver DRV1 with switching transistor M1 and rectification with the size of switching transistor M2.This is owing to from output driver DRV1, DRV2, drive the reason of coming work with switching transistor M1 and rectification with switching transistor M2 as capacity load.
In the DC-DC of present embodiment transducer, by above-mentioned such each transistor that constitutes output driver DRV1 and each the transistorized size that constitutes output driver DRV2 of designing, have to be suppressed at and drive with switching transistor M1 and rectification with switching transistor M2, reduce the advantage of spike noise respectively from ending the peak value of the electric current that transient flow is crossed when switching to conducting.
The present invention from its operation principle as can be known, even be applied to the DC-DC transducer that replaces the rectification among Fig. 1 to use the diode rectification of diode to use with transistor M2, also can obtain effect to a certain degree, but because when driving with switching transistor M1 conducting and rectification all produce spike noise under the both of these case during with switching transistor M2 conducting, so effect is more obvious when being applied to the DC-DC transducer of synchronous rectification mode.
More than, understand the invention that the inventor makes specifically according to execution mode, but the present invention is not limited to above-mentioned execution mode.For example, in order in switch element M1, M2, not flow through perforation electric current, (tf1 and tf2 and tr1 and tr2) do not generate GP1 and GP2 overlappingly during preferably making the variation of gate drive signal GP1 and GP2, therefore preferred forming circuit in this wise: that is, the output (or input) of output driver DRV1 and DRV2 is fed back to output control logic circuit 23, in the decline of confirming to begin after GP2 descends GP1, in the rising of confirming to begin after GP1 rises GP2.
And, when the time that switch element M1, M2 end simultaneously is long, in M2, flow through electric current in the body diode of parasitism, loss increases, therefore preferably shorten the time that becomes cut-off state simultaneously as far as possible, for this reason, desirable forming circuit as follows: that is, after GP2 descends, begin the decline of GP1 immediately, and after GP1 rises, begin the rising of GP2 immediately.
In addition, in the above-described embodiment, used the outer member that forms discretely with IC with power supply control as switch element M1, M2, be formed on IC with power supply control that (on-chip) element constitutes power drives IC on the sheet on the same semiconductor chip but also can use.And, represented in said embodiment to carry out the resistance R 1 of dividing potential drop, the situation of R2 at the output voltage that has formed on the chip being applied on the feedback terminal FB, but divider resistance R1, R2 also can be used as outer member, with dividing potential drop externally and voltage be applied on the feedback terminal.
In addition, represented the ON-OFF control circuit of the circuit of the built-in waveform signal (triangular wave) that generates input PWM comparator 22 on chip in said embodiment, but also can provide waveform signal or as the oscillator signal of its signal source from chip exterior.And, also can be applied to except that the PWM comparator, also to possess the PFM comparator, when underload, control the ON-OFF control circuit of the DC-DC transducer that carries out the voltage transformation action by PFM.
The example that applies the present invention to the buck DC-DC transducer has been described in the above description, but the present invention not only is defined in this, also can be applied to the counter-rotative type DC-DC transducer of booster type or generation negative voltage etc.
Claims (6)
1. an ON-OFF control circuit possesses first drive circuit, described first drive circuit generate to make driving that electric current flows through the inductor that voltage transformation uses with switch element carry out conducting, by the drive signal that drives, described ON-OFF control circuit is characterised in that,
Described first drive circuit generates drive signal as follows: compare from the transit time of the drive signal of conducting state when cut-off state shifts with switch element with making described driving, make described driving longer from the transit time of the drive signal of cut-off state when the conducting state transitions with switch element.
2. ON-OFF control circuit according to claim 1 is characterized in that,
Described ON-OFF control circuit also possesses second drive circuit, its be created on described driving with switch element be cut off during the electric current of coil is carried out the drive signal of the rectification of rectification with switch element,
Described second drive circuit generates drive signal as follows: compare from the transit time of the drive signal of conducting state when cut-off state shifts with switch element with making described rectification, make described rectification longer from the transit time of the drive signal of cut-off state when the conducting state transitions with switch element.
3. ON-OFF control circuit according to claim 2 is characterized in that,
Described driving is made of the P channel type field effect transistors with switch element, and described rectification is made of the N channel type field effect transistors with switch element,
Described first drive circuit is constituted: longer to low level transit time with comparing to the transit time of high level of the drive signal of exporting from this drive circuit from high level from low level,
Described second drive circuit is constituted:, longer to the transit time of high level from low level with comparing to low level transit time of the drive signal of exporting from this drive circuit from high level.
4. ON-OFF control circuit according to claim 3 is characterized in that,
Described first and second drive circuit constitutes by the CMOS inverter,
To form as the CMOS inverter of first drive circuit: the current driving capability of the current drives force rate N channel type field effect transistors of P channel type field effect transistors is big,
To form as the CMOS inverter of second drive circuit: the current driving capability of the current drives force rate P channel type field effect transistors of N channel type field effect transistors is big.
5. according to claim 3 or 4 described ON-OFF control circuit, it is characterized in that,
Drive signal in described first drive circuit from high level to low level transit time and from the drive signal of described second drive circuit output from the transit time of low level to high level, be below 5% of cycle of described drive signal.
6. a DC-DC transducer is characterized in that,
Possess:
The inductor that voltage transformation is used;
Make electric current flow through the driving switch element of this inductor;
This driving be cut off with switch element during the electric current of coil is carried out rectification the rectification switch element;
The filtering capacitor that is connected with lead-out terminal; And
Generate described driving with switch element and described rectification with the drive signal of switch element, each described ON-OFF control circuit in the claim 2～5.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2009020373A JP5304281B2 (en) | 2009-01-30 | 2009-01-30 | DC-DC converter and switching control circuit |
| JP2009-020373 | 2009-01-30 |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN101860208A true CN101860208A (en) | 2010-10-13 |
| CN101860208B CN101860208B (en) | 2014-07-02 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201010104741.6A Active CN101860208B (en) | 2009-01-30 | 2010-01-28 | DC-DC converter and switching control circuit |
Country Status (5)
| Country | Link |
|---|---|
| US (1) | US20100194371A1 (en) |
| EP (1) | EP2214298B1 (en) |
| JP (1) | JP5304281B2 (en) |
| KR (1) | KR101651993B1 (en) |
| CN (1) | CN101860208B (en) |
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN102170228A (en) * | 2011-04-29 | 2011-08-31 | 电子科技大学 | A dead time control circuit used in a DC-DC converter |
| CN102458000A (en) * | 2010-10-22 | 2012-05-16 | 精工爱普生株式会社 | Illumination device |
| CN102882372A (en) * | 2011-07-11 | 2013-01-16 | 凌力尔特公司 | Switching power supply having separate AC and DC current sensing paths |
| CN104488181A (en) * | 2012-07-27 | 2015-04-01 | 瑞典爱立信有限公司 | Control of a synchronous rectifier |
| CN106921283A (en) * | 2015-11-20 | 2017-07-04 | 丰田自动车株式会社 | On-off circuit |
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| WO2012023556A1 (en) * | 2010-08-20 | 2012-02-23 | シャープ株式会社 | Inverter |
| US9147701B2 (en) * | 2011-09-22 | 2015-09-29 | Raytheon Company | Monolithic InGaN solar cell power generation with integrated efficient switching DC-DC voltage convertor |
| KR101381631B1 (en) * | 2011-09-29 | 2014-04-04 | 주식회사엘디티 | Output voltage stability circuit of dc-dc converter |
| US9312820B2 (en) * | 2012-09-23 | 2016-04-12 | Dsp Group Ltd. | CMOS based TX/RX switch |
| KR101989575B1 (en) | 2012-12-07 | 2019-06-14 | 삼성전자주식회사 | Adaptive power converting device |
| KR101946386B1 (en) | 2012-12-11 | 2019-02-11 | 삼성전자주식회사 | Current mode pwm boost converter |
| EP2940847A1 (en) | 2014-04-30 | 2015-11-04 | Dialog Semiconductor GmbH | Method and apparatus for an adaptive threshold of a zero crossing comparator based on the current in the parasitic bipolar transistors |
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- 2010-01-11 KR KR1020100002226A patent/KR101651993B1/en active IP Right Grant
- 2010-01-26 US US12/693,642 patent/US20100194371A1/en not_active Abandoned
- 2010-01-27 EP EP10151726.6A patent/EP2214298B1/en not_active Not-in-force
- 2010-01-28 CN CN201010104741.6A patent/CN101860208B/en active Active
Cited By (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102458000A (en) * | 2010-10-22 | 2012-05-16 | 精工爱普生株式会社 | Illumination device |
| CN102170228A (en) * | 2011-04-29 | 2011-08-31 | 电子科技大学 | A dead time control circuit used in a DC-DC converter |
| CN102170228B (en) * | 2011-04-29 | 2013-06-12 | 电子科技大学 | Dead time control circuit used in a DC-DC converter |
| CN102882372A (en) * | 2011-07-11 | 2013-01-16 | 凌力尔特公司 | Switching power supply having separate AC and DC current sensing paths |
| CN102882372B (en) * | 2011-07-11 | 2015-03-25 | 凌力尔特公司 | Switching power supply having separate AC and DC current sensing paths |
| CN104488181A (en) * | 2012-07-27 | 2015-04-01 | 瑞典爱立信有限公司 | Control of a synchronous rectifier |
| CN106921283A (en) * | 2015-11-20 | 2017-07-04 | 丰田自动车株式会社 | On-off circuit |
| CN106921283B (en) * | 2015-11-20 | 2019-02-26 | 丰田自动车株式会社 | Switching circuit |
Also Published As
| Publication number | Publication date |
|---|---|
| JP2010178555A (en) | 2010-08-12 |
| US20100194371A1 (en) | 2010-08-05 |
| JP5304281B2 (en) | 2013-10-02 |
| EP2214298B1 (en) | 2018-04-18 |
| EP2214298A1 (en) | 2010-08-04 |
| KR101651993B1 (en) | 2016-08-29 |
| CN101860208B (en) | 2014-07-02 |
| KR20100088527A (en) | 2010-08-09 |
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